Avalanche Forecast
Issued: Dec 5th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
mconlan,
Avalanche Canada
Travel in avalanche terrain is not recommended during this warm and intense storm. A natural avalanche cycle may be ongoing.
Summary
Confidence
Avalanche Summary
Explosives triggered large wet loose avalanches on Tuesday. We expect that a natural avalanche cycle occurred on the buried weak layer of surface hoar described in the Snowpack Summary but we will have to wait for clearing skies for further observations. Continuing stormy conditions may continue this natural cycle wherever the weak layer remains intact.
Snowpack Summary
Stormy conditions continue with a high freezing level. Rain has soaked most of the snowpack to the mountain tops, which will switch to snow as the freezing level drops. This is loading between 10 to 30 cm of snow that overlies a touchy weak layer of feathery surface hoar. The intense storm is likely triggering many avalanches on this layer and perhaps squashing the layer elsewhere, but it may still linger in specific locations.
The remainder of the snowpack is generally weak and faceted, with a hard melt-freeze crust found near the base of the snowpack.
Snowpack depths are generally between 50 and 80 cm at treeline, which quickly tapers as you lower with elevation.
Weather Summary
Tuesday Night
Cloudy with 15 to 30 mm of rain or heavy snow near the mountain tops. Southwest alpine wind 20 to 40 km/h. Treeline temperature 1 °C. Freezing level 2300 m.
Wednesday
Cloudy with 15 to 30 cm of heavy snow or rain below the snow-rain line. Southwest alpine wind 20 to 30 km/h. Treeline temperature 0 °C. Freezing level 1900 m.
Thursday
Mostly cloudy with 5 to 15 cm of early-morning snow. West alpine wind 10 km/h. Treeline temperature -5 °C.
Friday
Mostly cloudy with 2 to 5 cm of snow. West alpine wind 10 to 20 km/h. Treeline temperature -7 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid avalanche terrain during periods of heavy rain.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
- Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.
Problems
Storm Slabs
Rain and heavy snow are rapidly loading a buried weak layer. Storm slab avalanches may release naturally. The most problematic terrain features will be wherever the snow surface is relatively smooth and uniform.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Loose wet avalanches are likely wherever you find a saturated snowpack.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Dec 6th, 2023 4:00PM
